Brief Summary

The Tetrephyllidea contains over 400 described species that parasitize elasmobranchs (sharks, skates, and stingrays). Nearly all elasmobranchs examined for cestodes have been found to be host to at least one species of tetraphyllidean tapeworm. Like other tapeworms, adult tetraphyllideans are found in the intestine of their hosts, where they live absorbing nutrients from their host through their body surfaces. No complete life cycle for tetraphllideans is known, but larvae have been found in teleosts, mollusks, crustaceans, and marine mammals. Perhaps the most impressive feature of the Tetraphyllidea is the incredibly variety of scolex morphology. The scolex is the anterior attachment organ used by tapeworms to remain attached the gut of their hosts. Scolex morphology is incredibly variable among the tetraphyllideans, it is usually comprised of four muscular bothridia that are often adorned with other attachment structures such as suckers and hooks. The diversity of hosts species that the tetraphyllideans parasitize, and the range of intestinal morphology found in those hosts is likely responsible, at least in part, for the diversity of scolex morphology present in this tapeworm order.